Time division duplex (tdd) subframe structure supporting single and multiple interlace modes

ABSTRACT

Aspects of the present disclosure provide a time division duplex (TDD) subframe structure that supports both single and multiple interlace modes of operation. In a single interlace mode, control information, data information corresponding to the control information and acknowledgement information corresponding to the data information are included in a single subframe. In a multiple interlace mode, at least one of the control information, the data information corresponding to the control information or the acknowledgement information corresponding to the data information is included in a different subframe. Both single and multiple interlace modes can be multiplexed together within the TDD subframe structure.

PRIORITY CLAIM

The present Application for Patent is a continuation of Non-Provisionalapplication Ser. No. 15/051,949 filed in the U.S. Patent and TrademarkOffice on Feb. 24, 2016, the entire content of which is incorporatedherein by reference as if fully set forth below in its entirety and forall applicable purposes. Non-Provisional application Ser. No. 15/051,949claims priority to Provisional Application No. 62/194,710 entitled “TimeDivision Duplex (TDD) Frame Structure Supporting Single and MultipleInterlace Modes” filed Jul. 20, 2015, and assigned to the assigneehereof and hereby expressly incorporated by reference herein.

TECHNICAL FIELD

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to supporting single andmultiple interlace modes in a time division duplex (TDD) subframestructure.

BACKGROUND

Wireless communication networks are widely deployed to provide variouscommunication services such as telephony, video, data, messaging,broadcasts, and so on. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of multiple-access technologies include codedivision multiple access (CDMA) systems, time division multiple access(TDMA) systems, frequency division multiple access (FDMA) systems,orthogonal frequency division multiple access (OFDMA) systems,single-carrier frequency division multiple access (SC-FDMA) systems, andtime division synchronous code division multiple access (TD-SCDMA)systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. Examples of telecommunication standardsinclude Long Term Evolution (LTE) and LTE-Advanced (LTE-A), whichinclude a set of enhancements to the Universal Mobile TelecommunicationsSystem (UMTS) mobile standard promulgated by Third GenerationPartnership Project (3GPP). LTE-A is designed to better support mobilebroadband Internet access by improving spectral efficiency, loweringcosts, improving services, making use of new spectrum, and betterintegrating with other open standards using OFDMA on the downlink (DL),SC-FDMA on the uplink (UL), and multiple-input multiple-output (MIMO)antenna technology.

However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in multipleaccess technology. For example, the spectrum allocated to wirelesscommunication networks employing multiple access technology is being (oris expected to be) allocated in such a way that paired carriers,utilized in many existing frequency division duplex (FDD) systems, areeither not available, or not available in matched bandwidthconfigurations. Accordingly, time division duplex (TDD) carriers areexpected to be utilized in many future deployments for wirelesscommunication systems.

BRIEF SUMMARY OF SOME EXAMPLES

The following presents a simplified summary of one or more aspects ofthe present disclosure, in order to provide a basic understanding ofsuch aspects. This summary is not an extensive overview of allcontemplated features of the disclosure, and is intended neither toidentify key or critical elements of all aspects of the disclosure norto delineate the scope of any or all aspects of the disclosure. Its solepurpose is to present some concepts of one or more aspects of thedisclosure in a simplified form as a prelude to the more detaileddescription that is presented later.

Various aspects of the present disclosure provide a time division duplex(TDD) subframe structure that supports both a single interlace mode ofoperation and a multiple interlace mode of operation. In the singleinterlace mode of operation, control information, data informationcorresponding to the control information and acknowledgement informationcorresponding to the data information are included in a single subframe.In the multiple interlace mode of operation, at least one of the controlinformation, the data information corresponding to the controlinformation or the acknowledgement information corresponding to the datainformation is included in a different subframe. Both single andmultiple interlace modes can be multiplexed together within the TDDsubframe structure.

In one aspect, the disclosure provides a method of wirelesscommunication in a wireless communication network for a subordinateentity to communicate with a scheduling entity utilizing a time divisionduplex (TDD) carrier, in which the TDD carrier includes a plurality ofsubframes. The method includes receiving first control information in acontrol portion of a first subframe, in which the first controlinformation includes a first downlink assignment for the subordinateentity. The method further includes receiving first data correspondingto the first downlink assignment in a data portion of the firstsubframe, and transmitting first acknowledgement informationcorresponding to the first data in an acknowledgement portion of thefirst subframe, in which the acknowledgement portion includes an end ofthe first subframe. The method further includes receiving second controlinformation scheduling a retransmission of at least part of the firstdata in the control portion of a second subframe immediately followingthe first subframe.

Another aspect of the disclosure provides a user equipment in a wirelesscommunication network. The user equipment includes a transceiver inwireless communication with a base station, a memory, and a processorcommunicatively coupled to the transceiver and the memory. The processoris configured to receive first control information in a control portionof a first subframe from the base station via the transceiver, in whichthe first control information includes a first downlink assignment forthe user equipment. The processor is further configured to receive firstdata corresponding to the first downlink assignment in a data portion ofthe first subframe from the base station via the transceiver, andtransmit first acknowledgement information corresponding to the firstdata in an acknowledgement portion of the first subframe to the basestation via the transceiver, in which the acknowledgement portionincludes an end of the first subframe. The processor is furtherconfigured to receive second control information scheduling aretransmission of at least part of the first data in the control portionof a second subframe immediately following the first subframe from thebase station via the transceiver.

Another aspect of the disclosure provides a subordinate entity in awireless communication network. The subordinate entity includes meansfor receiving first control information in a control portion of a firstsubframe, in which the first control information includes a firstdownlink assignment for the subordinate entity. The subordinate entityfurther includes means for receiving first data corresponding to thefirst downlink assignment in a data portion of the first subframe, andmeans for transmitting first acknowledgement information correspondingto the first data in an acknowledgement portion of the first subframe,in which the acknowledgement portion includes an end of the firstsubframe. The subordinate entity further includes means for receivingsecond control information scheduling a retransmission of at least partof the first data in the control portion of a second subframeimmediately following the first subframe.

These and other aspects of the invention will become more fullyunderstood upon a review of the detailed description, which follows.Other aspects, features, and embodiments of the present invention willbecome apparent to those of ordinary skill in the art, upon reviewingthe following description of specific, exemplary embodiments of thepresent invention in conjunction with the accompanying figures. Whilefeatures of the present invention may be discussed relative to certainembodiments and figures below, all embodiments of the present inventioncan include one or more of the advantageous features discussed herein.In other words, while one or more embodiments may be discussed as havingcertain advantageous features, one or more of such features may also beused in accordance with the various embodiments of the inventiondiscussed herein. In similar fashion, while exemplary embodiments may bediscussed below as device, system, or method embodiments it should beunderstood that such exemplary embodiments can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communicationnetwork architecture.

FIG. 2 is a block diagram conceptually illustrating an example of ascheduling entity communicating with one or more subordinate entitiesaccording to some embodiments.

FIG. 3 is a block diagram illustrating an example of a hardwareimplementation for a scheduling entity employing a processing systemaccording to some embodiments.

FIG. 4 is a block diagram illustrating an example of a hardwareimplementation for a subordinate entity employing a processing systemaccording to some embodiments.

FIG. 5 illustrates the structure of uplink (UL)-centric and downlink(DL)-centric TDD subframes that may be used in some wirelesscommunication networks.

FIG. 6 is a diagram illustrating a DL-centric TDD subframe structureimplementing a single interlace mode.

FIG. 7 is a diagram illustrating an example of a DL-centric TDD subframestructure implementing a multiple interlace mode.

FIG. 8 is a diagram illustrating an example of a DL-centric TDD subframestructure implementing a multiple interlace mode.

FIG. 9 is a diagram illustrating an example of a DL-centric TDD subframestructure implementing a multiple interlace mode.

FIG. 10 is a diagram illustrating an example of a DL-centric TDDsubframe structure implementing a multiple interlace mode.

FIG. 11 is a diagram illustrating an example of UL-centric andDL-centric TDD subframes implementing a multiple interlace mode.

FIG. 12 is a diagram illustrating an example of an UL-centric TDDsubframe structure implementing a multiple interlace mode.

FIG. 13 is a diagram illustrating an example of an UL-centric TDDsubframe structure implementing a multiple interlace mode.

FIG. 14 is a diagram illustrating an example of an UL-centric TDDsubframe structure implementing a multiple interlace mode.

FIG. 15 is a flow chart of a method of wireless communication utilizinga TDD subframe structure.

FIG. 16 is a flow chart of a method of wireless communication utilizinga TDD subframe structure in a single interlace mode of operation.

FIG. 17 is a flow chart of a method of wireless communication utilizinga TDD subframe structure in a multiple interlace mode of operation.

FIG. 18 is a flow chart of a method of wireless communication utilizinga TDD subframe structure in a multiple interlace mode of operation.

FIG. 19 is a flow chart of a method of wireless communication utilizinga TDD subframe structure in a multiple interlace mode of operation.

FIG. 20 is a flow chart of a method of wireless communication utilizinga TDD subframe structure in a multiple interlace mode of operation.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

The various concepts presented throughout this disclosure may beimplemented across a broad variety of telecommunication systems, networkarchitectures, and communication standards. In order to illustrate someof the entities or devices described throughout the present disclosure,FIG. 1 is a diagram illustrating a generalized example of a wirelesscommunication network 100. In this example, the wireless communicationnetwork 100 is divided into a number of cellular regions (cells) 102. Inthe context of a multiple access network, channel resources maygenerally be scheduled, and each entity may be synchronous. That is,each node utilizing the network may coordinate its usage of theresources such that transmissions are only made during the allocatedportion of the frame, and the time of each allocated portion issynchronized among the different nodes. One node in each cellular region102/110 acts as a scheduling entity.

Each scheduling entity 104/108 may be a base station or access point, ora user equipment (UE) 106 in a device-to-device (D2D) and/or meshnetwork. The scheduling entity 104/108 manages the resources on thecarrier and assigns resources to other users of the channel, includingsubordinate entities, such as one or more UEs 106 in the cellularnetwork 100. The scheduling entities 104 are responsible for all radiorelated functions including radio bearer control, admission control,mobility control, scheduling, security, and connectivity to acentralized controller and/or gateway. There is no centralizedcontroller in this example of a network 100, but a centralizedcontroller may be used in alternative configurations.

One or more lower power class scheduling entities 108 may have acellular region 110 that overlaps with one or more other cellularregions (cells) 102. The lower power class scheduling entity 108 may bea femto cell, pico cell, micro cell, remote radio head, or in someinstances, another UE 106. The macro scheduling entities 104 are eachassigned to a respective cell 102 and are configured to provide anaccess point to a core network for all the UEs 106 in the cells 102.

The modulation and multiple access scheme employed by the network 100may vary depending on the particular telecommunications standard beingdeployed. In some radio access networks, such as those defined in LTEstandards, orthogonal frequency division multiplexing (OFDM) is used onthe downlink (DL) and single carrier frequency division multiple access(SC-FDMA) is used on the uplink (UL) to support both frequency divisionduplexing (FDD) and time division duplexing (TDD). As those skilled inthe art will readily appreciate from the detailed description to follow,the various concepts presented herein are well suited for variousapplications including telecommunication standards employing othermodulation and multiple access techniques. By way of example, theseconcepts may be employed in 5G, LTE, or Evolution-Data Optimized(EV-DO). EV-DO is an air interface standard promulgated by the 3rdGeneration Partnership Project 2 (3GPP2) as part of the CDMA2000 familyof standards and employs CDMA to provide broadband Internet access tomobile stations. These concepts may also be extended to UniversalTerrestrial Radio Access (UTRA) employing Wideband-CDMA (W-CDMA) andother variants of CDMA, such as TD-SCDMA; Global System for MobileCommunications (GSM) employing TDMA; Evolved UTRA (E-UTRA), IEEE 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDM employingOFDMA. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents fromthe 3GPP organization. CDMA2000 is described in documents from the 3GPP2organization. The actual wireless communication standard and themultiple access technology employed will depend on the specificapplication and the overall design constraints imposed on the system.

The scheduling entities 104 may have multiple antennas supporting MIMOtechnology. The use of MIMO technology enables the scheduling entities104 to exploit the spatial domain to support spatial multiplexing,beamforming, and transmit diversity. Spatial multiplexing may be used totransmit different streams of data simultaneously on the same frequency.The data steams may be transmitted to a single UE 106 to increase thedata rate or to multiple UEs 106 to increase the overall systemcapacity. This is achieved by spatially precoding each data stream(i.e., applying a scaling of an amplitude and a phase) and thentransmitting each spatially precoded stream through multiple transmitantennas on the downlink (DL). The spatially precoded data streamsarrive at the UE(s) 106 with different spatial signatures, which enableseach of the UE(s) 106 to recover the one or more data streams destinedfor that UE 106. On the uplink (UL), each UE 106 transmits a spatiallyprecoded data stream, which enables the scheduling entity 104 toidentify the source of each spatially precoded data stream.

Spatial multiplexing is generally used when channel conditions are good.When channel conditions are less favorable, beamforming may be used tofocus the transmission energy in one or more directions. This may beachieved by spatially precoding the data for transmission throughmultiple antennas. To achieve good coverage at the edges of the cell, asingle stream beamforming transmission may be used in combination withtransmit diversity.

Certain aspects of a wireless communication network described herein mayrelate to a system supporting OFDM on the DL. OFDM is a spread-spectrumtechnique that modulates data over a number of subcarriers within anOFDM symbol. The subcarriers are spaced apart at precise frequencies.The spacing provides orthogonality that enables a receiver to recoverthe data from the subcarriers. In the time domain, a guard interval(e.g., cyclic prefix) may be added to each OFDM symbol to combatinter-OFDM-symbol interference. In some examples, the UL may use SC-FDMAin the form of a Discrete Fourier Transform (DFT)-spread OFDM signal tocompensate for high peak-to-average power ratio (PAPR). However, thoseof ordinary skill in the art will recognize that any suitable modulationand multiple access scheme may be utilized for uplink and downlinkcommunication.

Referring now to FIG. 2, a block diagram illustrates an exemplaryscheduling entity 202 in wireless communication with a plurality ofsubordinate entities 204. The scheduling entity 202 transmits downlinkdata channel(s) 206 and downlink control channel(s) 208, while thesubordinate entities 204 transmit uplink data channel(s) 210 and uplinkcontrol channel(s) 212. Of course, the channels illustrated in FIG. 2are not necessarily all of the channels that may be utilized between ascheduling entity 202 and subordinate entities 204, and those ofordinary skill in the art will recognize that other channels may beutilized in addition to those illustrated, such as other control andfeedback channels.

In accordance with aspects of the present disclosure, the term downlink(DL) may refer to a point-to-multipoint transmission originating at thescheduling entity 202. In addition, the term uplink (UL) may refer to apoint-to-point transmission originating at a subordinate entity 204.

Broadly, the scheduling entity 202 is a node or device responsible forscheduling traffic in a wireless communication network, including thedownlink transmissions and, in some examples, uplink data 210 from oneor more subordinate entities 204 to the scheduling entity 202. Ascheduling entity 202 may be, or may reside within, a base station, anetwork node, a user equipment (UE), an access terminal, or any suitablenode or peer in a wireless communication network.

Broadly, the subordinate entity 204 is a node or device that receivesscheduling control information, including but not limited to schedulinggrants, synchronization or timing information, or other controlinformation from another entity in the wireless communication networksuch as the scheduling entity 202. A subordinate entity may be, or mayreside within, a base station, a network node, a UE, an access terminal,or any suitable node or peer in a wireless communication network.

As illustrated in FIG. 2, the scheduling entity 202 may transmitdownlink data 206 to one or more subordinate entities 204. In addition,the subordinate entities 204 may transmit uplink data 210 to thescheduling entity 202. In accordance with aspects of the disclosure, theuplink data 210 and/or downlink data 206 may be transmitted intransmission time intervals (TTIs). As used herein, the term TTI refersto the period in which a block of data, corresponding to the smallestcollection of symbols to be processed at the Media Access Control (MAC)layer and above, is transferred by the physical layer onto the radiointerface. In accordance with aspects of the disclosure, a TTI is equalto the duration of a subframe. Thus, as further used herein, the termsubframe refers to an encapsulated set of information sent within asingle TTI that is capable of being independently decoded. In variousaspects, multiple subframes are grouped together to form a single frame.For example, in LTE, the TTI (subframe duration) is set to 1 ms, whereasthe frame duration is set to 10 ms, corresponding to 10 subframes.However, within the scope of the present disclosure, a subframe may havea duration of 250 μs, 500 μs, 1 ms, or any suitable duration. Similarly,any suitable number of subframes may occupy a frame. Frames aregenerally utilized by upper Open Systems Interconnection (OSI) layersfor synchronization and other purposes.

In one example, the scheduling entity 202 may multiplex downlink datafor a set of subordinate entities (i.e., two or more subordinateentities) within a single subframe. For example, the scheduling entity202 may multiplex downlink data to the set of subordinate entities usingtime division multiplexing, frequency division multiplexing (e.g.,OFDM), code division multiplexing, and/or any suitable multiplexingscheme known to those of ordinary skill in the art. Likewise, anysuitable multiple access scheme may be utilized to combine uplink datafrom multiple subordinate entities 204 within a single subframe.

The scheduling entity 202 may further broadcast downlink controlchannel(s) 208 to one or more subordinate entities 204. The downlinkcontrol channel(s) 208 may include in some examples a physical downlinkcontrol channel (PDCCH), a physical downlink shared channel (PDSCH)and/or any other control channels or pilots, such as the Channel StateInformation—Reference Signal (CSI-RS) pilot. In still a further example,the downlink control channel(s) 208 may include acknowledgementinformation (e.g., acknowledged (ACK)/not acknowledged (NACK) packets)indicating whether the uplink data 210 in one or more subframes wasreceived correctly at the scheduling entity 202. For example, a datapacket may include verification bits, such as a checksum and/or a cyclicredundancy check (CRC). Accordingly, a device receiving a data packetmay receive and decode the data packet and verify the integrity of thereceived and decoded packet in accordance with the verification bits.When the verification succeeds, a positive acknowledgment (ACK) may betransmitted; whereas when the verification fails, a negativeacknowledgment (NACK) may be transmitted.

Furthermore, each of the subordinate entities 204 may transmit uplinkcontrol channel(s) 212 to the scheduling entity 202. The uplink controlchannel(s) 212 may include in some examples a physical uplink controlchannel (PUCCH), random access channel (RACH), scheduling request (SR),sounding reference signal (SRS), channel quality indicator (CQI),channel state feedback information, buffer status information, or anyother suitable control information or signaling. In an aspect of thedisclosure, the uplink control channel(s) 212 may include a request forthe scheduling entity 202 to schedule uplink transmissions. Here, inresponse to the request transmitted on the uplink control channel(s)212, the scheduling entity 202 may transmit in the downlink controlchannel(s) 208 information that may schedule the TTI with uplinkpackets. In still a further example, the uplink control channel(s) 212may include acknowledgement information (e.g., acknowledged (ACK)/notacknowledged (NACK) packets) indicating whether the downlink data 206 inone or more subframes was received correctly at the subordinate entity204.

FIG. 3 is a conceptual diagram illustrating an example of a hardwareimplementation for a scheduling entity 202 employing a processing system314. In accordance with various aspects of the disclosure, an element,or any portion of an element, or any combination of elements may beimplemented with a processing system 314 that includes one or moreprocessors 304.

In various aspects of the disclosure, the scheduling entity 202 may beany suitable radio transceiver apparatus, and in some examples, may beembodied in a base station (BS), a base transceiver station (BTS), aradio base station, a radio transceiver, a transceiver function, a basicservice set (BSS), an extended service set (ESS), an access point (AP),a Node B, an eNode B (eNB), mesh node, relay, or some other suitableterminology. Within the present document, a base station may be referredto as a scheduling entity, indicating that the base station providesscheduling information to one or more subordinate entities. Such a basestation may provide a wireless access point to a core network for anynumber of subordinate entities.

In other examples, the scheduling entity 202 may be embodied by awireless user equipment (UE). Examples of a UE include a cellular phone,a smart phone, a session initiation protocol (SIP) phone, a laptop, anotebook, a netbook, a smartbook, a personal digital assistant (PDA), asatellite radio, a global positioning system (GPS) device, a multimediadevice, a video device, a digital audio player (e.g., MP3 player), acamera, a game console, an entertainment device, a vehicle component, awearable computing device (e.g., a smart watch, a health or fitnesstracker, etc.), an appliance, a sensor, a vending machine, or any othersimilar functioning device. The UE may also be referred to by thoseskilled in the art as a mobile station (MS), a subscriber station, amobile unit, a subscriber unit, a wireless unit, a remote unit, a mobiledevice, a wireless device, a wireless communications device, a remotedevice, a mobile subscriber station, an access terminal (AT), a mobileterminal, a wireless terminal, a remote terminal, a handset, a terminal,a user agent, a mobile client, a client, or some other suitableterminology. Within the present document, a UE may be referred to eitheras a scheduling entity, or a subordinate entity. That is, in variousaspects of the present disclosure, a wireless UE may operate as ascheduling entity providing scheduling information to one or moresubordinate entities, or may operate as a subordinate entity, operatingin accordance with scheduling information provided by a schedulingentity.

Examples of processors 304 include microprocessors, microcontrollers,digital signal processors (DSPs), field programmable gate arrays(FPGAs), programmable logic devices (PLDs), state machines, gated logic,discrete hardware circuits, and other suitable hardware configured toperform the various functionality described throughout this disclosure.That is, the processor 304, as utilized in a scheduling entity 202, maybe used to implement any one or more of the processes described below.

In this example, the processing system 314 may be implemented with a busarchitecture, represented generally by the bus 302. The bus 302 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 314 and the overall designconstraints. The bus 302 links together various circuits including oneor more processors (represented generally by the processor 304), amemory 305, and computer-readable media (represented generally by thecomputer-readable medium 306). The bus 302 may also link various othercircuits such as timing sources, peripherals, voltage regulators, andpower management circuits, which are well known in the art, andtherefore, will not be described any further. A bus interface 308provides an interface between the bus 302 and a transceiver 310. Thetransceiver 310 provides a means for communicating with various otherapparatus over a transmission medium. Depending upon the nature of theapparatus, a user interface 312 (e.g., keypad, display, speaker,microphone, joystick) may also be provided.

The processor 304 is responsible for managing the bus 302 and generalprocessing, including the execution of software stored on thecomputer-readable medium 306. The software, when executed by theprocessor 304, causes the processing system 314 to perform the variousfunctions described below for any particular apparatus. Thecomputer-readable medium 306 may also be used for storing data that ismanipulated by the processor 304 when executing software.

In some aspects of the disclosure, the processor 304 may includeresource assignment and subframe generation circuitry 341, configured togenerate, schedule, and modify a resource assignment or grant oftime-frequency resources. For example, the resource assignment andsubframe control circuitry 341 may generate one or more time divisionduplex (TDD) subframes, each including time-frequency resources assignedto carry data and/or control information to and/or from multiplesubordinate entities. The resource assignment and subframe generationcircuitry 341 may operate in coordination with resource assignment andsubframe generation software 351.

The processor 304 may further include downlink (DL) data and controlchannel generation and transmission circuitry 342, configured togenerate and transmit downlink data and control channels. The DL dataand control channel generation and transmission circuitry 342 mayoperate in coordination with the resource assignment and subframecontrol circuitry 341 to schedule the DL data and/or control informationand to place the DL data and/or control information onto a time divisionduplex (TDD) carrier within one or more subframes generated by theresource assignment and subframe generation circuitry 341 in accordancewith the resources assigned to the DL data and/or control information.The DL data and control channel generation and transmission circuitry342 may further operate in coordination with DL data and control channelgeneration and transmission software 352.

The processor 304 may further include uplink (UL) data and controlchannel reception and processing circuitry 343, configured to receiveand process uplink control channels and uplink data channels from one ormore subordinate entities. In some examples, the UL data and controlchannel reception and processing circuitry 343 may be configured toreceive scheduling requests from one or more subordinate entities, thescheduling requests being configured to request a grant oftime-frequency resources for uplink user data transmissions. In otherexamples, the UL data and control channel reception and processingcircuitry 343 may be configured to receive and process acknowledgementinformation (e.g., acknowledged/not acknowledged packets) from one ormore subordinate entities. The UL data and control channel reception andprocessing circuitry 343 may operate in coordination with the resourceassignment and subframe generation circuitry 341 to schedule UL datatransmissions, DL data transmissions and/or DL data retransmissions inaccordance with the received UL control channel information. The UL dataand control channel reception and processing circuitry 343 may furtheroperate in coordination with UL data and control channel reception andprocessing software 353.

The processor 304 may further include interlace mode configurationcircuitry 344, configured for providing at least a single interlace modeof operation, in which control, data and acknowledgement information isself-contained within a single TTI (or TDD subframe), and a multipleinterlace mode of operation, in which the control, data andacknowledgement information are contained within two or more TTIs (orTDD subframes) in an interlaced manner

In the single interlace mode of operation, a self-contained TDD subframestructure is utilized by the resource assignment and subframe controlcircuitry 341 to generate one or more self-contained subframes. In eachself-contained subframe, the control/scheduling information providescontrol/scheduling for all of the data packets within the subframe andthe acknowledgement information includes acknowledgement/notacknowledgement (ACK/NACK) signals for all of the data packets withinthe subframe. Therefore, the self-contained subframe structure mayinclude transmissions in both the uplink and the downlink directions.

In some examples, the self-contained TDD subframe structure includes DLcontrol (scheduling) information, DL data information corresponding tothe scheduling information and UL acknowledgement informationcorresponding to the data information. In other examples, theself-contained subframe structure includes DL control (scheduling)information, UL data information corresponding to the schedulinginformation and DL acknowledgement information corresponding to the datainformation.

In an aspect of the disclosure, a hybrid automatic repeat request (HARQ)retransmission scheme is used to retransmit data incorrectly received.Although the single interlace mode supports single HARQ interlaceprocessing at the physical layer to enable high data rates in extremebandwidth cases with a reasonable HARQ buffer cost, when the throughputof a subordinate entity is not at peak and/or when there is limited linkbudget, the processing timeline may be too tight for the subordinateentity to turn around HARQ in the same self-contained subframe. Forexample, when the subordinate entity is located at the edge of the cell,there may be limited downlink control and uplink ACK link budgets due tolimited bandwidth on the downlink and limited symbol duration on theuplink and downlink. These link budget limitations may prevent thesubordinate entity from returning the ACK/NACK within the same subframeas data reception.

Processing and/or power constraints at the scheduling entity may alsoprevent the scheduling entity from completing retransmissions to one ormore subordinate entities in the next subframe. For example, schedulingupdates for the next subframe based on ACK/NACK signals received in acurrent subframe may require fast processing at the scheduling entity.If there is not sufficient time to decode all of the ACK/NACK signalsbefore the next subframe, the scheduling entity may not be able toschedule all of the necessary retransmissions in the next subframe.

Therefore, to allow for longer processing time at the scheduling entityand/or subordinate entity, the interlace mode configuration circuitry344 may further provide a multiple interlace mode of operation. In themultiple interlace mode of operation, two or more TDD subframes areutilized by the resource assignment and subframe generation circuitry341 to transmit the control, data (or retransmitted data) andacknowledgement information. In various aspects of the disclosure, themultiple interlace mode enables at least one of the control, data, orACK information to be transmitted in an interlaced manner between two ormore TDD subframes. In some examples, the TDD subframe structureutilized in the multiple interlace mode of operation may be the same TDDsubframe structure utilized in the single interlace mode of operation.However, the TDD subframe structure may not be entirely self-contained,such that one or more of the control, data, or ACK information may betransmitted in a different subframe.

In some examples, the multiple interlace mode of operation enables dataretransmission to be delayed one or more subframes. Thus, instead ofscheduling retransmissions in back-to-back subframes, retransmissionsmay be scheduled in subsequent subframes (e.g., every other subframe orany other delayed scheduling configuration). In other examples, theACK/NACK information may be delayed one or more subframes (e.g., theACK/NACK portion in a particular subframe may correspond to datatransmitted in a previous subframe). In still other examples, thecontrol information may be prescheduled, such that the control portionof a particular subframe may correspond to data transmitted in asubsequent subframe. Similar multiple interlace mode arrangements may beimplemented for UL data transmissions and retransmissions. The interlacemode configuration circuitry 344 may operate in coordination withinterlace mode configuration software 354.

The processor 304 may further include interlace mode assignmentcircuitry 345, configured to assign a scheduling mode selected from thesingle and multiple interlace modes to each subordinate entity. Thescheduling mode assigned to a particular subordinate entity may dependon various factors, such as the throughput, buffer (e.g., hybridautomatic repeat request (HARQ) buffer size), and/or latencyrequirements of the subordinate entity, the power consumption and/orprocessing speed of the scheduling entity and/or the subordinate entityand the link budget of the uplink/downlink. The interlace modeassignment circuitry 345 may operate in coordination with interlace modeassignment software 355.

In an exemplary operation, the interlace mode assignment circuitry 345may assign the single interlace mode of operation or the multipleinterlace mode of operation to each subordinate entity for a currentsubframe based on the processing resources and/or constraints of thescheduling entity and/or subordinate entities, and in coordination withthe interlace mode configuration circuitry 344, provide the parametersdefining the assigned mode(s) of operation to the resource assignmentand subframe generation circuitry 341 for generation of the currentsubframe. The resource assignment and subframe generation circuitry 341may multiplex both single interlace subordinate entities and multipleinterlace subordinate entities within the current TDD subframe.

The resource assignment and subframe generation circuitry 341 mayfurther determine a TDD subframe structure for the current subframe. Insome examples, the resource assignment and subframe generation circuitry341 may determine whether the current subframe should include primarilyuplink (UL) data information or primarily downlink (DL) datainformation. When the resource assignment and subframe generationcircuitry 341 determines that the current subframe should includeprimarily DL data information, the resource assignment and subframegeneration circuitry 341 provides a TDD subframe structure that includesa DL control (scheduling) portion, a DL data portion and an ULacknowledgement portion. When the resource assignment and subframegeneration circuitry 341 determines that the current subframe shouldinclude primarily UL data information, the resource assignment andsubframe generation circuitry 341 provides a TDD subframe structure thatincludes a DL control (scheduling) portion, an UL data portion and a DLacknowledgement portion. In the single interlace mode of operation, theTDD subframe structure is self-contained. However, in the multipleinterlace mode of operation, the TDD subframe structure may enable atleast one of the control, data, or ACK information to be transmitted inan interlaced manner between two or more TDD subframes.

Based on the subframe structure and selected modes of operation for eachsubordinate entity for the current subframe, the DL data and controlchannel generation and transmission circuitry 342 may populate thecurrent subframe with control and/or data by preparing the controland/or data information in memory 305 and scheduling the control and/ordata information via the resource assignment and subframe generationcircuitry 341 for transmission according to the subframe structure andrespective interlace modes of each subordinate entity. The DL data andcontrol channel generation and transmission circuitry 342 may furthercoordinate with the UL data and control reception and processingcircuitry 343 to generate the current subframe, as described below.

In an aspect of the disclosure, when the subframe structure includes aDL data portion, the DL data and control channel generation andtransmission circuitry 342 may include DL control (scheduling)information in the control portion and DL data information in the dataportion of the subframe. For example, the DL data and control channelgeneration and transmission circuitry 342 may include DL control(scheduling) information by preparing the control (scheduling)information in memory 305 and loading the control (scheduling)information from memory 305 into the DL control portion of the subframe.The DL data and control channel generation and transmission circuitry342 may further include DL data information corresponding to the controlinformation included in the current subframe (e.g., in the singleinterlace mode of operation) or in a previous subframe (e.g., in themultiple interlace mode of operation) by preparing the DL datainformation in memory 305 and loading DL data information from memory305 into the DL data portion of the subframe. The control (scheduling)information may include control (scheduling) information for new DL datapackets and retransmitted DL data packets. As an example, the DL dataand control channel generation and transmission circuitry 342 mayfurther carry hybrid automatic repeat request (HARQ) configurationinformation within the control (scheduling) information forretransmitted DL data packets by preparing the HARQ configurationinformation in memory 305 and loading the HARQ configuration informationfrom memory 305 into the DL control portion of the current subframe. TheUL data and control channel reception and processing circuitry 343 maythen include acknowledgement information in the acknowledgement portionof the current subframe by receiving and processing ACK/NACK packetssent from one or more subordinate entities in the current subframe. TheACK/NACK packets may correspond to the DL data packets included in thecurrent subframe (e.g., in the single interlace mode of operation) or ina previous subframe (e.g., in the multiple interlace mode of operation).

In an aspect of the disclosure in which the subframe structure includesan UL data portion, the DL data and control channel generation andtransmission circuitry 342 may include DL control (scheduling)information in the control portion of the current subframe by preparingthe DL control (scheduling) information in memory 305 and loading thecontrol (scheduling) information from memory 305 into the DL controlportion. The UL data and control channel reception and processingcircuitry 343 may then include UL data information in the data portionof the current subframe by receiving and processing the UL datainformation sent from one or more subordinate entities. The UL datainformation may correspond to the control information included in thecurrent subframe (e.g., in the single interlace mode of operation) or ina previous subframe (e.g., in the multiple interlace mode of operation).The DL data and control channel generation and transmission circuitry342 may then include acknowledgement information corresponding to ULdata information received in the current subframe (e.g., in the singleinterlace mode of operation) or in a previous subframe (e.g., in themultiple interlace mode of operation) by preparing the acknowledgementinformation (ACK/NACK packets) in memory 305 and loading the ACK/NACKpackets from memory 305 into the acknowledgement portion of the currentsubframe.

The processor 304 may further include modulation and codingconfiguration circuitry 346, configured for determining a modulation andcoding scheme (MCS) to utilize for downlink transmissions and/or a MCSfor a subordinate entity to utilize for uplink transmissions. Themodulation and coding configuration circuitry 346 may operate incoordination with modulation and coding configuration software 356.

One or more processors 304 in the processing system may executesoftware. Software shall be construed broadly to mean instructions,instruction sets, code, code segments, program code, programs,subprograms, software modules, applications, software applications,software packages, routines, subroutines, objects, executables, threadsof execution, procedures, functions, etc., whether referred to assoftware, firmware, middleware, microcode, hardware descriptionlanguage, or otherwise. The software may reside on a computer-readablemedium 306. The computer-readable medium 306 may be a non-transitorycomputer-readable medium. A non-transitory computer-readable mediumincludes, by way of example, a magnetic storage device (e.g., hard disk,floppy disk, magnetic strip), an optical disk (e.g., a compact disc (CD)or a digital versatile disc (DVD)), a smart card, a flash memory device(e.g., a card, a stick, or a key drive), a random access memory (RAM), aread only memory (ROM), a programmable ROM (PROM), an erasable PROM(EPROM), an electrically erasable PROM (EEPROM), a register, a removabledisk, and any other suitable medium for storing software and/orinstructions that may be accessed and read by a computer. Thecomputer-readable medium may also include, by way of example, a carrierwave, a transmission line, and any other suitable medium fortransmitting software and/or instructions that may be accessed and readby a computer. The computer-readable medium 306 may reside in theprocessing system 314, external to the processing system 314, ordistributed across multiple entities including the processing system314. The computer-readable medium 306 may be embodied in a computerprogram product. By way of example, a computer program product mayinclude a computer-readable medium in packaging materials. Those skilledin the art will recognize how best to implement the describedfunctionality presented throughout this disclosure depending on theparticular application and the overall design constraints imposed on theoverall system.

FIG. 4 is a conceptual diagram illustrating an example of a hardwareimplementation for an exemplary subordinate entity 204 employing aprocessing system 414. In accordance with various aspects of thedisclosure, an element, or any portion of an element, or any combinationof elements may be implemented with a processing system 414 thatincludes one or more processors 404.

The processing system 414 may be substantially the same as theprocessing system 314 illustrated in FIG. 3, including a bus interface408, a bus 402, memory 405, a processor 404, and a computer-readablemedium 406. Furthermore, the subordinate entity 204 may include a userinterface 412 and a transceiver 410 substantially similar to thosedescribed above in FIG. 3. The processor 404, as utilized in asubordinate entity 204, may be used to implement any one or more of theprocesses described below.

In some aspects of the disclosure, the processor 404 may include uplink(UL) data and control channel generation and transmission circuitry 442,configured to generate and transmit uplink data on an UL data channel,and to generate and transmit uplink control/feedback/acknowledgementinformation on an UL control channel. The UL data and control channelgeneration and transmission circuitry 442 may operate in coordinationwith UL data and control channel generation and transmission software452. The processor 404 may further include downlink (DL) data andcontrol channel reception and processing circuitry 444, configured forreceiving and processing downlink data on a data channel, and to receiveand process control information on one or more downlink controlchannels. In some examples, received downlink data and/or controlinformation may be temporarily stored in a data buffer 415 within memory405. The DL data and control channel generation and transmissioncircuitry 444 may operate in coordination with DL data and controlchannel generation and transmission software 454.

The processor 404 may further include interlace mode determinationcircuitry 446, configured for requesting and/or determining an interlacemode assigned to the subordinate entity. In an aspect of the disclosure,the interlace mode determination circuitry 446 may request a multipleinterlace mode of operation when the throughput of the subordinateentity is not at peak and/or when there is limited link budget. Theinterlace mode determination circuitry 446 may operate in coordinationwith the interlace mode determination software 456.

FIG. 5 illustrates exemplary structures of TDD subframes 500 and 510.The TDD subframes 500 and 510 may have a fixed duration (t), but mayalso be configurable and determined during network deployment and/or maybe updated through control messages or system messages. In one example,the duration of the TDD subframe 500 may be 500 μs. Of course, anysuitable subframe duration may be utilized within the scope of thepresent disclosure.

A transmitter-scheduled subframe, referred to herein as a downlink TTIsubframe or DL-centric subframe 500, may be used to carry downlinkcontrol and data information to one or more subordinate entities, whichmay be UEs for example, and also to receive acknowledgement information(e.g., ACK/NACK signals) from the subordinate entity or entities. Thus,each DL-centric subframe includes both DL transmissions and ULtransmissions and is divided with respect to time (t) into DLtransmission and UL transmission portions. A receiver-scheduledsubframe, referred to herein as an uplink TTI subframe or UL-centricsubframe 510, may be used to receive downlink control information fromthe scheduling entity, transmit uplink data to a scheduling entity, andreceive a downlink ACK/NACK signal for the transmitted data from thescheduling entity. Thus, each UL-centric subframe 510 also includes bothDL transmissions and UL transmissions and is divided with respect totime (t) into DL transmission and UL transmission portions.

In the example of the DL-centric subframe 500 shown in FIG. 5, the DLtransmission portions include a control portion 502 and a data portion504, and the UL transmission portions include an acknowledgement(ACK/NACK) portion 508. Therefore, within the subframe structure of FIG.5, the scheduling entity first has an opportunity to transmitcontrol/scheduling information in the control portion 502, and then anopportunity to transmit data in the DL data portion 504. Following aguard period (GP) portion 506, the scheduling entity has an opportunityto receive acknowledged (ACK)/not acknowledged (NACK) signals (ACK/NACKpackets) from subordinate entities using the carrier. This framestructure is downlink-centric, as more resources are allocated fortransmissions in the downlink direction (e.g., transmissions from thescheduling entity) than for transmissions in the uplink direction (e.g.,transmissions from the subordinate entities).

In one example, the control information portion 502 may be used totransmit a physical downlink control channel (PDCCH) indicatingtime-frequency assignments of data packets intended for one or moresubordinate entities in the current subframe 500 and/or subsequentsubframe(s), and the DL data portion 504 may be used to transmit a datapayload including the data packets intended for the one or moresubordinate entities within the assigned time-frequency slots of thecurrent subframe 500 and/or subsequent subframe(s). Thus, eachsubordinate entity that will be receiving data in the data portion 504of the subframe 500 may be individually addressed in the control portion502 of the current subframe 500 and/or previous subframe(s), so that thesubordinate entities can receive and process the correct downlink datapackets. Following the GP portion 506, the scheduling entity may receivean ACK signal (or a NACK signal) during the ACK/NACK portion 508 fromeach subordinate entity that received data packets during the dataportion 504 of the current subframe and/or previous subframe(s) toindicate whether the data packets were successfully received.

In other examples, the control portion 502 may be used to transmit otherdownlink control channels and/or other downlink pilots, such as thechannel state information—reference signal (CSI-RS). These additionaldownlink channels and/or pilots, along with any other downlink controlinformation, may be transmitted together with the PDCCH within thecontrol portion 502. Broadly, any suitable transmission in the DLdirection may be made complementary to the control information describedabove within the control portion 502. In addition, the ACK/NACK portion508 may also be used for transmission of other uplink control channelsand information, such as the physical uplink control channel (PUCCH),random access channel (RACH), scheduling request (SR), soundingreference signal (SRS), channel quality indicator (CQI), channel statefeedback information and buffer status. Broadly, any suitabletransmission in the UL direction may be made complementary to theACK/NACK and other information described above within the ACK/NACKportion 508.

In an aspect of the disclosure, the data portion 504 may be used tomultiplex DL data transmissions to a set of subordinate entities (i.e.,two or more subordinate entities) within the subframe 500. For example,the scheduling entity may multiplex downlink data to the set ofsubordinate entities using time division multiplexing (TDM), frequencydivision multiplexing (FDM) (i.e., OFDM), code division multiplexing(CDM), and/or any suitable multiplexing scheme known to those ofordinary skill in the art. Thus, the DL data portion 504 may includedata for multiple users and up to a high order of multi-user MIMO. Inaddition, the control portion 502 and ACK/NACK portion 508 may also beused to multiplex control information to or from a set of subordinateentities in a TDM, FDM, CDM, and/or other suitable manner

The GP portion 506 may be scheduled to accommodate variability in UL andDL timing. For example, latencies due to RF antenna direction switching(e.g., from DL to UL) and RF settling (e.g., settling of phase lockloops, filters and power amplifiers), along with transmission pathlatencies, may cause the subordinate entity to transmit early on the ULto match DL timing. Such early transmission may interfere with symbolsreceived from the scheduling entity. Accordingly, the GP portion 506 mayallow an amount of time after the DL data portion 504 to preventinterference, where the GP portion 506 may provide an appropriate amountof time for the scheduling entity to switch its RF antenna direction,for the over-the-air (OTA) transmission time, and time for ACKprocessing by the subordinate entity. The GP portion 506 may furtherprovide an appropriate amount of time for the subordinate entity toswitch its RF antenna direction (e.g., from DL to UL), to process thedata payload, and for the over-the-air (OTA) transmission time.

The duration of the GP portion 506 may be configurable based on, forexample, the cell size and/or processing time requirements. For example,the GP portion 506 may have a duration of one symbol period (e.g., 31.25μs). However, in accordance with aspects of the disclosure, the switchpoint from DL to UL transmissions may be deterministic throughout thenetwork. Thus, although the beginning point of the GP portion 506 may bevariable and configurable, the ending point of the GP portion 506corresponding to the switch point from DL transmissions to ULtransmissions may be fixed by the network to manage interference betweenDL and UL transmissions. In an aspect of the disclosure, the switchpoint may be updated by the network in a semi-static manner andindicated in the PDCCH. In addition, the GP duration and/or beginningpoint of the GP portion 506 may also be indicated in the PDCCH.

In the example of the UL-centric subframe 510 shown in FIG. 5, the DLtransmission portions include a control portion 512 and anacknowledgement portion 520, and the UL transmission portions include adata portion 516. Therefore, within the UL-centric subframe structureshown in FIG. 5, the subordinate entity first has an opportunity toreceive control information in the control portion 512. Following a GPportion 514, the subordinate entity has an opportunity to transmit datain the UL data portion 516, and following another GP portion 518, toreceive acknowledgement information (e.g., an ACK/NACK signal) in theACK/NACK portion 520. This frame structure is uplink-centric, as moreresources are allocated for transmissions in the uplink direction (e.g.,transmissions from the subordinate entity) than in the downlinkdirection (e.g., transmissions from the scheduling entity).

In one example, the control information portion 512 may be used totransmit a physical downlink control channel (PDCCH) indicatingtime-frequency assignments of data packets to be transmitted by one ormore subordinate entities in the current subframe 510 and/or subsequentsubframe(s), and the data portion 516 may be used to by the subordinateentities to transmit their data packets to the scheduling entity withinthe assigned time-frequency slots in the current subframe 510 and/orsubsequent subframe(s). Each subordinate entity that transmitted datawithin the data portion 516 may then receive an ACK signal (or a NACKsignal) during the ACK/NACK portion 520 of the current subframe 510and/or subsequent subframe(s) from the scheduling entity to indicatewhether the data packets were successfully received at the schedulingentity.

In other examples, the control portion 512 and/or ACK/NACK portion 520may be used to transmit other downlink control channels and informationand/or data from other layers. In addition, the data portion 516 mayalso be used to transmit uplink control channels and information. Forexample, the control portion 512 of a subframe 510 may carry a datatransmission (e.g., a small payload of data) for a subordinate entity,such as an application layer (or layer other than the physical layer)ACK from a previous subframe. The subordinate entity may thenacknowledge the data transmission in the data portion 516 of the samesubframe 510 and/or subsequent subframe(s).

In an aspect of the disclosure, the UL data portion 516 may be used tocarry data transmissions from a set of subordinate entities (i.e., twoor more subordinate entities) within the subframe 510 using one or moreof TDMA, FDMA, CDMA, or any other suitable multiple access scheme. Thus,the UL data portion 516 may include packets from multiple users and upto a high order of multi-user MIMO. In addition, the control portion 512and ACK/NACK portion 520 may also be used to carry control informationto a set of subordinate entities in a TDMA, FDMA, CDMA, or othersuitable multiple access manner In an aspect of the disclosure, UL dataprocessing at the scheduling entity may be amortized over the entireTTI. For example, the control portion 512, the ACK/NACK portion 520, andpart of the GP portion 514 may all be used to decode UL data in the dataportion 516.

FIG. 6 is a diagram illustrating a DL-centric TDD subframe structure 600implementing a single interlace mode. In the single interlace mode,downlink (DL)-centric subframes 601 and 603 are each self-contained,such that control information, data information corresponding to thecontrol information and ACK information corresponding to the datainformation are all included within a single DL-centric subframe 601 or603. For example, control information may be transmitted by thescheduling entity in a control information portion 602 of a firstDL-centric subframe 601, data information corresponding to the controlinformation (as indicated by the arrow pointing from the control portion602 to a data portion 604) may be transmitted by the scheduling entityin the data portion 604 of the first DL-centric subframe 601, andacknowledgement information corresponding to the data information (asindicated by the arrow pointing from the data portion 604 to an ACK/NACKportion 606) may be received by the scheduling entity from subordinateentities in the ACK/NACK portion 606 of the first DL-centric subframe601.

Based on the ACK/NACK information received in the ACK/NACK portion 606of the first DL-centric subframe 601, the scheduling entity generatescontrol information for a control portion 608 of a next (second)DL-centric subframe 603 (as indicated by the arrow pointing from theACK/NACK portion 606 to the control portion 608). For example, if theACK/NACK information includes a NACK signal, at least part of the codedbits of the data information transmitted in the data portion 604 of thefirst DL-centric subframe 601 may be retransmitted in a data portion 610of the second DL-centric subframe 603.

FIG. 7 is a diagram illustrating a DL-centric TDD subframe structure 700implementing a multiple interlace mode that provides additionalprocessing time in the scheduling entity by delaying HARQ retransmissionfor one or more subframes. In FIG. 7, each DL-centric TDD subframe 701,703, and 705 may be self-contained. However, retransmissions are notscheduled in back-to-back subframes. Instead, retransmissions may bescheduled in subsequent subframes (e.g., every other subframe or anyother delayed scheduling configuration).

For example, the first DL-centric subframe 701 may be self-containedsuch that control information in a control information portion 702, datainformation corresponding to the control information (as indicated bythe arrow pointing from the control portion 702 to a data portion 704)and acknowledgement information corresponding to the data information(as indicated by the arrow pointing from the data portion 704 to anACK/NACK portion 706) may be included in the first DL-centric subframe701. However, to allow for additional ACK/NACK processing time in thescheduling entity, instead of scheduling HARQ retransmissions in thenext DL-centric subframe 703, the scheduling entity can delayretransmission until DL-centric subframe 705 for one or more subordinateentities. For example, based on the ACK/NACK information received fromone or more subordinate entities in the ACK/NACK portion 706 of thefirst DL-centric subframe 701, the scheduling entity may schedule thenext transmission for those one or more subordinate entities inDL-centric subframe 705 (as indicated by the arrow pointing from theACK/NACK portion 706 to the control portion 708 of DL-centric subframe705).

In an aspect of the disclosure, the scheduling entity may multiplex bothsingle interlace subordinate entities and multiple interlace subordinateentities within TDD subframes 701, 703, and 705. For example, thescheduling entity may schedule high throughput subordinate entities inthe single interlace mode and low throughput subordinate entities in themultiple interlace mode. The high throughput subordinate entities may bescheduled, for example, in DL-centric frames 701, 703, and 705, whilelow throughput subordinate entities may be scheduled in DL-centricframes 701 and 705. In an additional aspect, for one or more of thesingle interlace subordinate entities, the scheduling entity may utilizepre-generated waveforms for HARQ retransmission and/or new transmissionsto ensure the scheduling entity meets the scheduling timelinerequirements for the single interlace mode subordinate entities.

FIG. 8 is a diagram illustrating a TDD subframe structure 800implementing a multiple interlace mode that provides additionalprocessing time in the subordinate entity by delaying ACK/NACKinformation for one or more subframes. In FIG. 8, although theDL-centric TDD subframe structure remains the same, each DL-centricsubframe 801, 803, and 805 may not be self-contained. Instead, theACK/NACK portion in a particular subframe may correspond to datatransmitted in a previous subframe.

For example, in the first DL-centric subframe 801, data information in adata portion 804 corresponds to control information in a control portion802 (as indicated by the arrow pointing from the control portion 802 toa data portion 804). However, to allow for additional data processingtime in one or more subordinate entities, instead of scheduling ACK/NACKsignals for those one or more subordinate entities in the firstDL-centric subframe 801, the scheduling entity can schedule ACK/NACKsignals in the next DL-centric subframe 803 or in any other subsequentDL-centric subframe. In the example shown in FIG. 8, the ACK/NACKsignals from those one or more subordinate entities can be received bythe scheduling entity in the acknowledgement portion 806 of the secondDL-centric subframe 803. Then, based on the ACK/NACK informationreceived in the ACK/NACK portion 806 of the second DL-centric subframe803, the scheduling entity may schedule the next transmission for thoseone or more subordinate entities in DL-centric subframe 805 (asindicated by the arrow pointing from the ACK/NACK portion 806 to thecontrol portion 808 of DL-centric subframe 805) or in any othersubsequent DL-centric subframe.

In an aspect of the disclosure, the scheduling entity may multiplex bothsingle interlace subordinate entities and multiple interlace subordinateentities within TDD subframes 801, 803, and 805. For example, thescheduling entity may schedule high throughput subordinate entities inthe single interlace mode and low throughput subordinate entities in themultiple interlace mode. The high throughput subordinate entities may bescheduled to transmit ACK/NACK in TDD subframes 801, 803, and 805, whilelow throughput subordinate entities may be scheduled to transmitACK/NACK in TDD subframe 803. In an additional aspect, the schedulingentity may multiplex single interlace, ACK-delayed multiple interlaceand control-delayed multiple interlace subordinate entities within TDDsubframes 801, 803, and 805. The scheduling entity may further delayboth the control and ACK for one or more subordinate entities andmultiplex such control/ACK-delayed multiple interlace subordinateentities with single interlace subordinate entities and other types ofmultiple interlace subordinate entities (ACK-delayed and/orcontrol-delayed).

FIG. 9 is a diagram illustrating a DL-centric TDD subframe structure 900implementing a multiple interlace mode in which the control informationis prescheduled. In FIG. 9, although the DL-centric TDD subframestructure remains the same, each DL-centric subframe 901 and 903 may notbe self-contained. Instead, the control portion of a particular subframemay correspond to data transmitted in a subsequent subframe.

For example, control information in a control portion 902 of a firstDL-centric subframe 901 may correspond to data information in a dataportion 904 of a second DL-centric subframe 903 (as indicated by thearrow pointing from the control portion 902 to the data portion 904).The acknowledgement information corresponding to the data informationmay be included in the acknowledgement portion 906 of the secondDL-centric subframe 903 (as indicated by the arrow pointing from thedata portion 904 to the acknowledgement portion 906) or may be includedin a subsequent subframe to extend the processing time of thesubordinate entity. In addition, although not shown, retransmissionsand/or new transmissions may be scheduled in a next DL-centric subframeafter the second DL-centric subframe 903 or in any subsequent DL-centricsubframe to extend the processing time of the scheduling entity.

In an aspect of the disclosure, prescheduling the control informationmay support efficient micro-sleep and dynamic bandwidth switching byproviding a delay between the control information and the datainformation. This delay enables the subordinate entity to wake up andopen a larger bandwidth receiver before receipt of the data. Thesubordinate entity may monitor the control channel and enter into amicro-sleep state when no control grant is detected.

FIG. 10 is a diagram illustrating a DL-centric TDD subframe structure1000 implementing a control-prescheduled multiple interlace mode thatsupports an enhanced physical downlink control channel (ePDCCH) 1002.With an ePDCCH, control information may be spread out, e.g., over theentire subframe to boost the downlink control channel link budget. Forexample, control information corresponding to an ePDCCH 1002 mayoverlap, in time, both a control portion 1004 and a data portion 1006 ofa first DL-centric subframe 1001. In one example, as illustrated in FIG.10, the control information in the ePDCCH 1002 may be multiplexed withthe control and data portions 1004 and 1006, respectively, usingFrequency Division Multiplexing (FDM) relative to the control and dataportions. In other examples, the control information in the ePDCCH 1002may be multiplexed with the control and data portions 1004 and 1006 by ascrambling code using Code Division Multiplexing (CDM); or the controlinformation in the ePDCCH 1002 may be multiplexed with the control anddata portions 1004 and 1006, respectively, using Time DivisionMultiplexing (TDM).

Data information corresponding to the control information may then beincluded in a data portion 1008 of a next (second) DL-centric subframe1003 (as indicated by the arrow pointing from the control portions1004/1006 to the data portion 1008). The acknowledgement informationcorresponding to the data information may be included in theacknowledgement portion 1010 of the second DL-centric subframe 1003 (asindicated by the arrow pointing from the data portion 1006 to theacknowledgement portion 1008) or may be included in a subsequentsubframe to extend the processing time of the subordinate entity. Inaddition, although not shown, retransmissions and/or new transmissionsmay be scheduled in a next DL-centric subframe after the secondDL-centric subframe 1003 or in any subsequent DL-centric subframe toextend the processing time of the scheduling entity.

In an aspect of the disclosure, the scheduling entity may multiplexcontrol-prescheduled multiple interlace subordinate entities with singleinterlace subordinate entities and other types of multiple interlacesubordinate entities within the same TDD subframe structure. Forexample, the scheduling entity may schedule high throughput subordinateentities in the single interlace mode and low throughput subordinateentities in the control-prescheduled and/or control/ACK-delayed multipleinterlace mode.

FIG. 11 is a diagram illustrating an UL-centric TDD subframe structure1100 implementing a multiple interlaced mode in which the UL ACK ischannelized in an UL-centric subframe 1107. For example, the ACKs fromone or more DL-centric subframes 1101, 1103, and 1105 may be groupedtogether and transmitted within a data portion 1111 of an UL-centricsubframe 1107. In an aspect of the disclosure, channelizing the ACKs insome of the UL-centric subframes 1107 may boost the ACK link budget byenabling an increase in the duration and/or number of ACK symbols. Inother aspects, the ACKs may be bundled over multipleDL-centric/UL-centric subframes. For example, systematic ACKs may besent in each DL-centric subframe, and parity ACKs (e.g., redundancyversions of the systematic ACKs) may be sent in some DL-centricsubframes and/or UL-centric subframes to further improve the efficiencyof the ACKs. Coding may also be used across these ACKs to improve thereliability of the ACKs.

Similarly, DL ACKs from one or more UL-centric subframes may be groupedtogether and transmitted within the control, data, and/or ACK portion ofa DL-centric subframe. For example, the DL ACK from UL-centric subframe1107 may be transmitted within the control, data, and/or ACK portion ofDL-centric subframe 1109.

In addition to acknowledgement information, data and/or schedulinginformation may also be transmitted between UL-centric and DL-centricsubframes. In one example, a DL data retransmission corresponding to aNACK in the ACK portion of a DL-centric subframe may be included withinan UL-centric subframe. Similarly, an UL data retransmissioncorresponding to a NACK in the ACK portion of an UL-centric subframe maybe included within a DL-centric subframe. In another example, schedulinginformation for data to be transmitted within a DL-centric subframe maybe included within a prior UL-centric subframe (and vice-versa).

FIG. 12 is a diagram illustrating an UL-centric TDD subframe structure1200 implementing a multiple interlace mode that provides additionalprocessing time in the scheduling entity by delaying DL ACK/NACK one ormore subframes. In FIG. 12, although the UL-centric TDD subframestructure remains the same, each UL-centric TDD subframe 1201 and 1203may not be self-contained. Instead, the DL ACK/NACK portion in aparticular UL-centric subframe may correspond to data transmitted in aprevious UL-centric subframe.

For example, in the first UL-centric subframe 1201, data informationtransmitted by subordinate entities in a data portion 1204 correspondsto control information transmitted by the scheduling entity in a controlportion 1202 (as indicated by the arrow pointing from the controlportion 1202 to a data portion 1204). However, to allow for additionaldata processing time by the scheduling entity, instead of scheduling DLACK/NACK signals transmitted by the scheduling entity in the firstsubframe 1201, the scheduling entity can schedule ACK/NACK signals inthe next UL-centric subframe 1203. Thus, the ACK/NACK signals can besent to the subordinate entities in the acknowledgement portion 1206 ofthe second UL-centric subframe 1203 (as indicated by the arrow pointingfrom the data portion 1204 to the acknowledgement portion 1206).

FIG. 13 is a diagram illustrating an UL-centric TDD subframe structure1300 implementing a multiple interlace mode that provides additionalprocessing time in the subordinate entities and relaxed scheduling inthe scheduling entity by delaying UL retransmissions one or moresubframes. In FIG. 13, although the UL-centric TDD subframe structureremains the same, each UL-centric TDD subframe 1301, 1303, and 1305 maynot be self-contained. Instead, UL retransmissions may be scheduled insubsequent UL-centric subframes (e.g., every other UL-centric subframeor any other delayed scheduling configuration).

For example, in the first UL-centric subframe 1301, data informationtransmitted by subordinate entities in a data portion 1304 correspondsto control information transmitted by the scheduling entity in a controlportion 1302 (as indicated by the arrow pointing from the controlportion 1302 to a data portion 1304). In addition, acknowledgementinformation transmitted by the scheduling entity and corresponding tothe data information may be included in the acknowledgement (ACK/NACK)portion 1306 of the first UL-centric subframe 1301 (as indicated by thearrow pointing from the data portion 1304 to the ACK/NACK portion 1306).However, to allow for additional ACK/NACK processing time in thesubordinate entities, instead of scheduling HARQ retransmissions in thenext TDD subframe 1303, the scheduling entity can delay retransmissionuntil UL-centric TDD subframe 1305 for one or more subordinate entities(as indicated by the arrow pointing from the ACK/NACK portion 1306 tothe control portion 1308 of UL-centric subframe 1305).

In an aspect of the disclosure, the scheduling entity may multiplex bothsingle interlace subordinate entities and multiple interlace subordinateentities within UL-centric TDD subframes. For example, the schedulingentity may schedule high throughput subordinate entities in the singleinterlace mode and low throughput subordinate entities in the multipleinterlace mode. The high throughput subordinate entities may bescheduled to transmit data in UL-centric subframes 1301, 1303, and 1305,while low throughput subordinate entities may be scheduled to transmitdata in UL-centric subframes 1301 and 1303. In an additional aspect, thescheduling entity may multiplex single interlace, ACK-delayed multipleinterlace and control-delayed multiple interlace subordinate entitieswithin UL-centric subframes 1301, 1303, and 1305. The scheduling entitymay further delay both the DL control and DL ACK for one or moresubordinate entities and multiplex such control/ACK-delayed multipleinterlace subordinate entities with single interlace subordinateentities and other types of multiple interlace subordinate entities(ACK-delayed and/or control-delayed).

FIG. 14 is a diagram illustrating an UL-centric TDD subframe structure1400 implementing a multiple interlace mode in which the controlinformation is prescheduled to relax the control/data processingtimeline in the subordinate entities. In FIG. 14, although theUL-centric TDD subframe structure remains the same, each UL-centric TDDsubframe 1401 and 1403 may not be self-contained. Instead, the controlportion of a particular UL-centric subframe may correspond to datatransmitted by one or more subordinate entities in a subsequentUL-centric subframe.

For example, control information transmitted by a scheduling entity in acontrol portion 1402 of a first UL-centric subframe 1401 may correspondto data information transmitted by one or more subordinate entities in adata portion 1404 of a second UL-centric subframe 1403 (as indicated bythe arrow pointing from the control portion 1402 to the data portion1404). The acknowledgement information transmitted by the schedulingentity and corresponding to the data information may be included in theacknowledgement portion 1406 of the second DL-centric subframe 1403 ormay be included in a subsequent UL-centric subframe to extend theprocessing time of the scheduling entity. In addition, although notshown, retransmissions and/or new transmissions by subordinate entitiesmay be scheduled in a next UL-centric subframe after the secondDL-centric subframe 1403 or in a subsequent UL-centric subframe toextend the processing time of the scheduling entity.

FIG. 15 is a flow chart 1500 of a method of wireless communicationutilizing a TDD subframe structure. The method may be performed by ascheduling entity as described above and illustrated in FIGS. 2 and 3,by a processor or processing system, or by any suitable means forcarrying out the described functions.

At block 1502, the scheduling entity provides a single interlace mode ofoperation. For example, with reference to FIGS. 5 and 6, the singleinterlace mode of operation may include a self-contained UL-centricand/or DL-centric TDD subframe structure in which the controlinformation, data information corresponding to the control information,and acknowledgement information corresponding to the data informationare transmitted within a single TDD subframe.

At block 1504, the scheduling entity provides a multiple interlace modeof operation. In various aspects, with reference to FIGS. 7-14, themultiple interlace mode of operation may include the same basicUL-centric and/or DL-centric TDD subframe structure as the singleinterlace mode, but with one or more of the control, data, oracknowledgement information transmitted in a separate UL-centric orDL-centric TDD subframe.

At block 1506, the scheduling entity determines a respective schedulingmode for each subordinate entity from the single interlace and multipleinterlace modes. In an aspect of the disclosure, the scheduling entityconsiders one or more factors when assigning a particular schedulingmode to a subordinate entity. Examples of factors may include, but arenot limited to, throughput requirements, HARQ buffer requirements,latency requirements, processing speed of both the subordinate andscheduling entities, power consumption requirements of both thesubordinate and scheduling entities, whether the subordinate entity hasentered a micro-sleep mode, and the link budget of the uplink anddownlink. The scheduling mode may be statically determined ordynamically updated periodically, based upon scheduling requirements ofthe scheduling entity, or upon request from the subordinate entity.

At block 1508, the scheduling entity schedules transmissions to thesubordinate entities by multiplexing the scheduling modes assigned tothe subordinate entities within a TDD subframe structure. For example,single interlace subordinate entities may be scheduled to transmitACK/NACK signals in each DL-centric TDD subframe or data in eachUL-centric TDD subframe, while each interlace of multiple interlacesubordinate entities may be scheduled to transmit ACK/NACK signals inalternating DL-centric TDD subframes or data in alternating UL-centricsubframes (with multiple interlaces alternating between adjacentsubframes).

FIG. 16 is a flow chart 1600 of a method of wireless communicationutilizing a TDD subframe structure in a single interlace mode ofoperation. The method may be performed by a scheduling entity asdescribed above and illustrated in FIGS. 2 and 3, by a processor orprocessing system, or by any suitable means for carrying out thedescribed functions.

At block 1602, the scheduling entity determines the scheduling mode fora subordinate entity is a single interlace mode of operation. In thesingle interlace mode of operation, a self-contained TDD subframestructure is utilized to generate a self-contained subframe. Forexample, with reference to FIGS. 5 and 6, the self-contained subframestructure may be a DL-centric subframe or an UL-centric subframe, inwhich the control information, data information corresponding to thecontrol information and acknowledgement information corresponded to thedata information are included within a single TDD subframe.

At block 1604, the scheduling entity generates a subframe having theself-contained subframe structure and includes control information inthe control portion of the subframe. For a DL-centric subframe, thecontrol information may include a PDCCH indicating the time-frequencyresource assignments for data transmissions from the scheduling entityto the subordinate entity. For an UL-centric subframe, the controlinformation may include a PDCCH indicating the time-frequency resourceassignments for data transmissions from the subordinate entity to thescheduling entity. In addition, other downlink control information mayalso be included within the control portion.

At block 1606, data information corresponding to the control informationis included in the data portion of the subframe. For example, in aDL-centric subframe, the data information may include data packetstransmitted to the subordinate entity on a downlink data channel In anUL-centric subframe, the data information may include data packetstransmitted from the subordinate entity on an uplink data channel

At block 1608, acknowledgement information corresponding to the datainformation is included in the acknowledgement portion of the subframe.For example, in a DL-centric subframe, an ACK/NACK message from thesubordinate entity that received data in the data portion of thesubframe may be included in the acknowledgement portion of the subframeto indicate whether the subordinate entity correctly received thedownlink data. In an UL-centric subframe, the acknowledgementinformation may include an ACK/NACK message to the subordinate entitythat transmitted data in the data portion of the subframe to indicatewhether the scheduling entity correctly received the uplink data.

FIG. 17 is a flow chart 1700 of a method of wireless communicationutilizing a TDD subframe structure in a multiple interlace mode ofoperation. The method may be performed by a scheduling entity asdescribed above and illustrated in FIGS. 2 and 3, by a processor orprocessing system, or by any suitable means for carrying out thedescribed functions.

At block 1702, the scheduling entity determines the scheduling mode fora subordinate entity is a multiple interlace mode of operation. In themultiple interlace mode of operation, two or more TDD subframes areutilized to transmit the control, data (or retransmitted data) andacknowledgement information. Although the subframe structure in themultiple interlace mode of operation may be the same as that in thesingle interlace mode of operation, the subframe structure may not beentirely self-contained.

At block 1704, the scheduling entity generates a first subframe andincludes control information in the control portion of the firstsubframe. For a DL-centric subframe, the control information may includea PDCCH indicating the time-frequency resource assignments for datatransmissions from the scheduling entity to the subordinate entity. Foran UL-centric subframe, the control information may include a PDCCHindicating the time-frequency resource assignments for datatransmissions from the subordinate entity to the scheduling entity. Inaddition, other downlink control information may also be included withinthe control portion.

At block 1706, data information corresponding to the control informationis included in the data portion of the first subframe. For example, in aDL-centric subframe, the data information may include data packetstransmitted to the subordinate entity on a downlink data channel In anUL-centric subframe, the data information may include data packetstransmitted from the subordinate entity on an uplink data channel

At block 1708, acknowledgement information corresponding to the datainformation is included in the acknowledgement portion of the subframe.For example, in a DL-centric subframe, an ACK/NACK message from thesubordinate entity that received data in the data portion of thesubframe may be included in the acknowledgement portion of the subframeto indicate whether the subordinate entity correctly received thedownlink data. In an UL-centric subframe, the acknowledgementinformation may include an ACK/NACK message to the subordinate entitythat transmitted data in the data portion of the subframe to indicatewhether the scheduling entity correctly received the uplink data.

At block 1710, when a NACK is included in the acknowledgementinformation, the scheduling entity generates a second subframesubsequent to the first subframe and retransmits the data from the firstsubframe in a data portion of the second subframe. As shown in FIGS. 7and 13, the second subframe may be separated in time from the firstsubframe by at least one intermediate subframe.

FIG. 18 is a flow chart 1800 of a method of wireless communicationutilizing a TDD subframe structure in a multiple interlace mode ofoperation. The method may be performed by a scheduling entity asdescribed above and illustrated in FIGS. 2 and 3, by a processor orprocessing system, or by any suitable means for carrying out thedescribed functions.

At block 1802, the scheduling entity determines the scheduling mode fora subordinate entity is a multiple interlace mode of operation. In themultiple interlace mode of operation, two or more TDD subframes areutilized to transmit the control, data (or retransmitted data) andacknowledgement information. Although the subframe structure in themultiple interlace mode of operation may be the same as that in thesingle interlace mode of operation, the subframe structure may not beentirely self-contained.

At block 1804, the scheduling entity generates a first subframe andincludes control information in the control portion of the firstsubframe. For a DL-centric subframe, the control information may includea PDCCH indicating the time-frequency resource assignments for datatransmissions from the scheduling entity to the subordinate entity. Foran UL-centric subframe, the control information may include a PDCCHindicating the time-frequency resource assignments for datatransmissions from the subordinate entity to the scheduling entity. Inaddition, other downlink control information may also be included withinthe control portion.

At block 1806, data information corresponding to the control informationis included in the data portion of the first subframe. For example, in aDL-centric subframe, the data information may include data packetstransmitted to the subordinate entity on a downlink data channel In anUL-centric subframe, the data information may include data packetstransmitted from the subordinate entity on an uplink data channel

At block 1808, the scheduling entity generates a second subframesubsequent to the first subframe and includes acknowledgementinformation corresponding to the data information in the acknowledgementportion of the second subframe. For example, in a DL-centric subframe asshown in FIG. 8, an ACK/NACK message from the subordinate entity thatreceived data in the data portion of the first subframe may be includedin the acknowledgement portion of the second subframe to indicatewhether the subordinate entity correctly received the downlink data. Inan UL-centric subframe as shown in FIG. 12, the acknowledgementinformation may include an ACK/NACK message to the subordinate entitythat transmitted data in the data portion of the first subframe toindicate whether the scheduling entity correctly received the uplinkdata.

FIG. 19 is a flow chart 1900 of a method of wireless communicationutilizing a TDD subframe structure in a multiple interlace mode ofoperation. The method may be performed by a scheduling entity asdescribed above and illustrated in FIGS. 2 and 3, by a processor orprocessing system, or by any suitable means for carrying out thedescribed functions.

At block 1902, the scheduling entity determines the scheduling mode fora subordinate entity is a multiple interlace mode of operation. In themultiple interlace mode of operation, two or more TDD subframes areutilized to transmit the control, data (or retransmitted data) andacknowledgement information. Although the subframe structure in themultiple interlace mode of operation may be the same as that in thesingle interlace mode of operation, the subframe structure may not beentirely self-contained.

At block 1904, the scheduling entity generates a first subframe andincludes control information in the control portion of the firstsubframe. For a DL-centric subframe, the control information may includea PDCCH indicating the time-frequency resource assignments for datatransmissions from the scheduling entity to the subordinate entity. Foran UL-centric subframe, the control information may include a PDCCHindicating the time-frequency resource assignments for datatransmissions from the subordinate entity to the scheduling entity. Inaddition, other downlink control information may also be included withinthe control portion.

At block 1906, the scheduling entity generates a second subframesubsequent to the first subframe and includes data informationcorresponding to the control information in the data portion of thesecond subframe. For example, in a DL-centric subframe as shown in FIGS.9 and 10, the data information may include data packets transmitted tothe subordinate entity on a downlink data channel In an UL-centricsubframe as shown in FIG. 14, the data information may include datapackets transmitted from the subordinate entity on an uplink datachannel

At block 1908, acknowledgement information corresponding to the datainformation is included in the acknowledgement portion of the secondsubframe. For example, in a DL-centric subframe as shown in FIG. 9, anACK/NACK message from the subordinate entity that received data in thedata portion of the second subframe may be included in theacknowledgement portion of the second subframe to indicate whether thesubordinate entity correctly received the downlink data. In anUL-centric subframe as shown in FIG. 14, the acknowledgement informationmay include an ACK/NACK message to the subordinate entity thattransmitted data in the data portion of the first subframe to indicatewhether the scheduling entity correctly received the uplink data.

FIG. 20 is a flow chart 2000 of a method of wireless communicationutilizing a TDD subframe structure in a multiple interlace mode ofoperation. The method may be performed by a scheduling entity asdescribed above and illustrated in FIGS. 2 and 3, by a processor orprocessing system, or by any suitable means for carrying out thedescribed functions.

At block 2002, the scheduling entity determines the scheduling mode fora subordinate entity is a multiple interlace mode of operation. In themultiple interlace mode of operation, two or more TDD subframes areutilized to transmit the control, data (or retransmitted data) andacknowledgement information. Although the subframe structure in themultiple interlace mode of operation may be the same as that in thesingle interlace mode of operation, the subframe structure may not beentirely self-contained.

At block 2004, the scheduling entity generates a DL-centric subframe andincludes control information in the control portion of the DL-centricsubframe. For example, the control information may include a PDCCHindicating the time-frequency resource assignments for datatransmissions from the scheduling entity to the subordinate entity.

At block 2006, data information corresponding to the control informationis included in the data portion of the DL-centric subframe. For example,the data information may include data packets transmitted to thesubordinate entity on a downlink data channel.

At block 2008, the scheduling entity generates an UL-centric subsequentto the DL-centric subframe and includes acknowledgement informationcorresponding to the data information in the UL-centric subframe. Forexample, as shown in FIG. 11, an ACK/NACK message from the subordinateentity that received data in the data portion of the DL-centric subframemay be included in the data portion of the UL-centric subframe toindicate whether the subordinate entity correctly received the downlinkdata.

As those skilled in the art will readily appreciate, various aspectsdescribed throughout this disclosure may be extended to any suitabletelecommunication system, network architecture, and communicationstandard. By way of example, various aspects may be applied to UMTSsystems such as W-CDMA, TD-SCDMA, and TD-CDMA. Various aspects may alsobe applied to systems employing Long Term Evolution (LTE) (in FDD, TDD,or both modes), LTE-Advanced (LTE-A) (in FDD, TDD, or both modes),CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband(UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20,Ultra-Wideband (UWB), Bluetooth, and/or other suitable systems,including those described by yet-to-be defined wide area networkstandards. The actual telecommunication standard, network architecture,and/or communication standard employed will depend on the specificapplication and the overall design constraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean“serving as an example, instance, or illustration.” Any implementationor aspect described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other aspects of thedisclosure. Likewise, the term “aspects” does not require that allaspects of the disclosure include the discussed feature, advantage ormode of operation. The term “coupled” is used herein to refer to thedirect or indirect coupling between two objects. For example, if objectA physically touches object B, and object B touches object C, thenobjects A and C may still be considered coupled to one another—even ifthey do not directly physically touch each other. For instance, a firstdie may be coupled to a second die in a package even though the firstdie is never directly physically in contact with the second die. Theterms “circuit” and “circuitry” are used broadly, and intended toinclude both hardware implementations of electrical devices andconductors that, when connected and configured, enable the performanceof the functions described in the present disclosure, without limitationas to the type of electronic circuits, as well as softwareimplementations of information and instructions that, when executed by aprocessor, enable the performance of the functions described in thepresent disclosure.

One or more of the components, steps, features and/or functionsillustrated in FIGS. 1-20 may be rearranged and/or combined into asingle component, step, feature or function or embodied in severalcomponents, steps, or functions. Additional elements, components, steps,and/or functions may also be added without departing from novel featuresdisclosed herein. The apparatus, devices, and/or components illustratedin FIGS. 1-4 may be configured to perform one or more of the methods,features, or steps described herein. The novel algorithms describedherein may also be efficiently implemented in software and/or embeddedin hardware.

It is to be understood that the specific order or hierarchy of steps inthe methods disclosed is an illustration of exemplary processes. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the methods may be rearranged. The accompanyingmethod claims present elements of the various steps in a sample order,and are not meant to be limited to the specific order or hierarchypresented unless specifically recited therein.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but are to be accorded the full scope consistentwith the language of the claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. A phrase referring to“at least one of” a list of items refers to any combination of thoseitems, including single members. As an example, “at least one of: a, b,or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, band c. All structural and functional equivalents to the elements of thevarious aspects described throughout this disclosure that are known orlater come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. No claim element is tobe construed under the provisions of 35 U.S.C. §112(f), unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.”

What is claimed is:
 1. A method of wireless communication in a wirelesscommunication network for a subordinate entity to communicate with ascheduling entity utilizing a time division duplex (TDD) carrier,wherein the TDD carrier comprises a plurality of subframes, the methodcomprising: receiving first control information in a control portion ofa first subframe, wherein the first control information comprises afirst downlink assignment for the subordinate entity; receiving firstdata corresponding to the first downlink assignment in a data portion ofthe first subframe; transmitting first acknowledgement informationcorresponding to the first data in an acknowledgement portion of thefirst subframe, wherein the acknowledgement portion comprises an end ofthe first subframe; and receiving second control information schedulinga retransmission of at least part of the first data in the controlportion of a second subframe following the first subframe.
 2. The methodof claim 1, wherein the second subframe immediately follows the firstsubframe, and further comprising: receiving the retransmission of the atleast part of the first data in the data portion of the second subframe;and transmitting second acknowledgement information corresponding to theretransmission of the at least part of the first data in theacknowledgement portion of the second subframe.
 3. The method of claim2, wherein the retransmission utilizes a pre-generated waveform.
 4. Themethod of claim 1, further comprising: receiving third controlinformation in the control portion of a third subframe subsequent to thesecond subframe, wherein the third control information comprises asecond downlink assignment for the subordinate entity; receiving seconddata corresponding to the second downlink assignment in the data portionof the third subframe; transmitting second acknowledgement informationcorresponding to the second data in the acknowledgement portion of thethird subframe; and receiving fourth control information scheduling anew transmission of new data in the control portion of a fourth subframeimmediately following the third subframe.
 5. The method of claim 1,wherein at least one intermediate subframe separates the second subframein time from the first subframe.
 6. The method of claim 1, furthercomprising: receiving third control information in the control portionof a third subframe subsequent to the second subframe, wherein the thirdcontrol information comprises a second downlink assignment for thesubordinate entity; receiving second data corresponding to the seconddownlink assignment in the data portion of the third subframe; andtransmitting second acknowledgement information corresponding to thesecond data in the acknowledgement portion of a fourth subframesubsequent to the third subframe.
 7. The method of claim 6, furthercomprising: receiving a retransmission of at least part of the seconddata in the data portion of a fifth subframe subsequent to the fourthsubframe.
 8. The method of claim 1, further comprising: receiving thirdcontrol information in the control portion of a third subframesubsequent to the second subframe, wherein the third control informationcomprises a second downlink assignment for the subordinate entity;receiving second data corresponding to the second downlink assignment inthe data portion of a fourth subframe subsequent to the third subframe;and transmitting second acknowledgement information corresponding to thesecond data in the acknowledgement portion of the fourth subframe. 9.The method of claim 8, wherein receiving the third control informationfurther comprises receiving the third control information in both thecontrol portion and the data portion of the third subframe.
 10. Themethod of claim 1, further comprising: receiving third controlinformation in the control portion of a third subframe subsequent to thesecond subframe, wherein the third subframe comprises a downlink-centricsubframe, wherein the third control information comprises a seconddownlink assignment for the subordinate entity; receiving second datacorresponding to the second downlink assignment in the data portion ofthe downlink-centric subframe; and transmitting second acknowledgementinformation corresponding to the second data in an uplink data portionof an uplink-centric subframe subsequent to the downlink-centricsubframe.
 11. A user equipment in a wireless communication network,comprising: a transceiver in wireless communication with a base station;a memory; and a processor communicatively coupled to the transceiver andthe memory, wherein the processor is configured to: receive firstcontrol information in a control portion of a first subframe from thebase station via the transceiver, wherein the first control informationcomprises a first downlink assignment for the user equipment; receivefirst data corresponding to the first downlink assignment in a dataportion of the first subframe from the base station via the transceiver;transmit first acknowledgement information corresponding to the firstdata in an acknowledgement portion of the first subframe to the basestation via the transceiver, wherein the acknowledgement portioncomprises an end of the first subframe; and receive second controlinformation scheduling a retransmission of at least part of the firstdata in the control portion of a second subframe following the firstsubframe from the base station via the transceiver.
 12. The userequipment of claim 11, wherein the second subframe immediately followsthe first subframe, and wherein the processor is further configured to:receive the retransmission of the at least part of the first data in thedata portion of the second subframe; and transmit second acknowledgementinformation corresponding to the retransmission of the at least part ofthe first data in the acknowledgement portion of the second subframe.13. The user equipment of claim 12, wherein the retransmission utilizesa pre-generated waveform.
 14. The user equipment of claim 11, whereinthe processor is further configured to: receive third controlinformation in the control portion of a third subframe subsequent to thesecond subframe, wherein the third control information comprises asecond downlink assignment for the user equipment; receive second datacorresponding to the second downlink assignment in the data portion ofthe third subframe; transmit second acknowledgement informationcorresponding to the second data in the acknowledgement portion of thethird subframe; and receive fourth control information scheduling a newtransmission of new data in the control portion of a fourth subframeimmediately following the third subframe.
 15. The user equipment ofclaim 11, wherein at least one intermediate subframe separates thesecond subframe in time from the first subframe.
 16. The user equipmentof claim 11, wherein the processor is further configured to: receivethird control information in the control portion of a third subframesubsequent to the second subframe, wherein the third control informationcomprises a second downlink assignment for the user equipment; receivesecond data corresponding to the second downlink assignment in the dataportion of the third subframe; and transmit second acknowledgementinformation corresponding to the second data in the acknowledgementportion of a fourth subframe subsequent to the third subframe.
 17. Theuser equipment of claim 16, wherein the processor is further configuredto: receive a retransmission of at least part of the second data in thedata portion of a fifth subframe subsequent to the fourth subframe. 18.The user equipment of claim 11, wherein the processor is furtherconfigured to: receive third control information in the control portionof a third subframe subsequent to the second subframe, wherein the thirdcontrol information comprises a second downlink assignment for the userequipment; receive second data corresponding to the second downlinkassignment in the data portion of a fourth subframe subsequent to thethird subframe; and transmit second acknowledgement informationcorresponding to the second data in the acknowledgement portion of thefourth subframe.
 19. The user equipment of claim 18, wherein theprocessor is further configured to receive the third control informationin both the control portion and the data portion of the third subframe.20. The user equipment of claim 11, wherein the processor is furtherconfigured to: receive third control information in the control portionof a third subframe subsequent to the second subframe, wherein the thirdsubframe comprises a downlink-centric subframe, wherein the thirdcontrol information comprises a second downlink assignment for the userequipment; receive second data corresponding to the second downlinkassignment in the data portion of the downlink-centric subframe; andtransmit second acknowledgement information corresponding to the seconddata in an uplink data portion of an uplink-centric subframe subsequentto the downlink-centric subframe.
 21. A non-transitory computer-readablemedium storing computer executable code, comprising code for causing asubordinate entity in a wireless communication network to: receive firstcontrol information in a control portion of a first subframe, whereinthe first control information comprises a first downlink assignment forthe subordinate entity; receive first data corresponding to the firstdownlink assignment in a data portion of the first subframe; transmitfirst acknowledgement information corresponding to the first data in anacknowledgement portion of the first subframe, wherein theacknowledgement portion comprises an end of the first subframe; andreceive second control information scheduling a retransmission of atleast part of the first data in the control portion of a second subframefollowing the first subframe.
 22. The non-transitory computer-readablemedium of claim 21, wherein the second subframe immediately follows thefirst subframe, and further comprising code for causing the subordinateentity to: receive the retransmission of the at least part of the firstdata in the data portion of the second subframe; and transmit secondacknowledgement information corresponding to the retransmission of theat least part of the first data in the acknowledgement portion of thesecond subframe.
 23. The non-transitory computer-readable medium ofclaim 22, wherein the retransmission utilizes a pre-generated waveform.24. The non-transitory computer-readable medium of claim 21, furthercomprising code for causing the subordinate entity to: receive thirdcontrol information in the control portion of a third subframesubsequent to the second subframe, wherein the third control informationcomprises a second downlink assignment for the subordinate entity;receive second data corresponding to the second downlink assignment inthe data portion of the third subframe; transmit second acknowledgementinformation corresponding to the second data in the acknowledgementportion of the third subframe; and receive fourth control informationscheduling a new transmission of new data in the control portion of afourth subframe immediately following the third subframe.
 25. Thenon-transitory computer-readable medium of claim 21, wherein at leastone intermediate subframe separates the second subframe in time from thefirst subframe.
 26. The non-transitory computer-readable medium of claim21, further comprising code for causing the subordinate entity to:receive third control information in the control portion of a thirdsubframe subsequent to the second subframe, wherein the third controlinformation comprises a second downlink assignment for the subordinateentity; receive second data corresponding to the second downlinkassignment in the data portion of the third subframe; and transmitsecond acknowledgement information corresponding to the second data inthe acknowledgement portion of a fourth subframe subsequent to the thirdsubframe.
 27. The non-transitory computer-readable medium of claim 26,further comprising code for causing the subordinate entity to: receive aretransmission of at least part of the second data in the data portionof a fifth subframe subsequent to the fourth subframe.
 28. Thenon-transitory computer-readable medium of claim 21, further comprisingcode for causing the subordinate entity to: receive third controlinformation in the control portion of a third subframe subsequent to thesecond subframe, wherein the third control information comprises asecond downlink assignment for the subordinate entity; receive seconddata corresponding to the second downlink assignment in the data portionof a fourth subframe subsequent to the third subframe; and transmitsecond acknowledgement information corresponding to the second data inthe acknowledgement portion of the fourth subframe.
 29. Thenon-transitory computer-readable medium of claim 28, further comprisescode for causing the subordinate entity to receive the third controlinformation in both the control portion and the data portion of thethird subframe.
 30. The non-transitory computer-readable medium of claim21, further comprising code for causing the subordinate entity to:receive third control information in the control portion of a thirdsubframe subsequent to the second subframe, wherein the third subframecomprises a downlink-centric subframe, wherein the third controlinformation comprises a second downlink assignment for the subordinateentity; receive second data corresponding to the second downlinkassignment in the data portion of the downlink-centric subframe; andtransmit second acknowledgement information corresponding to the seconddata in an uplink data portion of an uplink-centric subframe subsequentto the downlink-centric subframe.